The prevalence of alcohol abuse and alcoholism among different ethnic groups varies widely. Asian populations appear to have lower rates of alcoholism than other ethnic groups, whereas certain tribes of Native Americans have very high rates of alcohol abuse. These differences in rates of alcoholism between different ethnic groups are thought to reflect a combination of sociocultural and biological factors. Several studies have provided evidence to suggest that there may be racial and ethnic differences in biologic sensitivity to ethanol. The source of this disparity in ethanol sensitivity, while not well understood, presumably is the result of genetic differences in metabolic factors as well as differences in CNS "reactivity." The overall objective of the proposed studies is to extend our previous investigations, which had evaluated reaction to ethanol in Caucasian sons of alcoholics, to the study of Asian and Native American men. Genotyping for differences in alcohol metabolizing enzymes as well as ethanol reactivity will be evaluated using an ethanol challenge protocol. The specific aims of this investigation are: 1) To recruit a group of ASIAN men from the general community and who are 18-25 years of age and who are free of medical and psychiatric disorders. 2) To recruit a group of ASIAN and NATIVE AMERICAN MEN who are 16-25 years of age who are free of medical and psychiatric disorders. 3) To genotype all subjects for the presence of ALDH2, ADH2, and ADH3 alleles. 4) To carefully screen all subjects on personal history variables and to determine if any family history of alcoholism or other psychiatric disorders exist in first- and second-degree relatives. 5) To identify subgroups within the Asian and Native American populations for study. Within the Asian population, family history negative nonflushers (ALDH2*1 homozygotes) and flushers (heterozygotes and homozygotes for the ALDH2*2 allele) will be determined as well as some family history positive men. Within the Native American population, family history positive and negative individuals will be identified as well as those with possible differences in ADH2 or ADH3 alleles. 6) To test response to ethanol and placebo challenge in these matched sub-groups using behavioral, neuroendocrine, and electrophysiologic measures. 7) To follow-up both groups of men to determine if they develop changes in alcohol drinking patterns or alcohol related problems over the course of the study.